The fouling of heat transfer surfaces in kraft recovery boilers is a significant concern for the pulp and paper industry. The usual approach to controlling fouling is the use of so-called ``sootblowers,'' that utilize boiler steam to generate supersonic steam jets that are literally used to knock deposits off of the boiler tubes. About 3 to 10\% of the total steam produced in a recovery boiler is used for sootblowing. This high energy cost demands that they be operated as efficiently as possible. It is thus essential to devise improved strategies for maximizing sootblower efficiency and minimizing steam consumption. To achieve this, the behaviour of sootblower jets, and the effects of various parameters on sootblowing, must be well understood. This thesis documents a study of the performance of sootblower jets using numerical simulation; CFDLib 3.02, a CFD code from the Los Alamos National Laboratory, was used for the simulations. This work had two main parts. In the first part, sootblower jets that perform at the design condition (fully-expanded jets) were studied; in the second part, the study was extended to off-design (under/over-expanded) sootblower jets. In the first part, a compressibility-corrected version of CFDLib was validated against a wide range of available experimental data, of subsonic and fully-expanded supersonic free and impinging jets; simulations successfully predicted all of the cases. This compressibility-corrected model was then deemed suitable for modeling the fluid mechanics of fully-expanded sootblower jets, and so was used to study the effects of two parameters on sootblower jets: the lance pressure, and the rate of rotation of a sootblower. To study the effect of the lance pressure, numerical simulation was used to model fully-expanded sootblower jets corresponding to a range of lance pressures. To study the effect of rotation, the equations of motion were modified by adding the Coriolis and centrifugal terms, so that computations could be performed in a rotating frame of reference. Simulations were then run to study a fully-expanded sootblower jet operating at different rotation rates. The results indicate that sootblowers operate more efficiently at lower lance pressures, and that the rate of rotation does not significantly affect the structure of a sootblower jet. In the second part, the study was extended to sootblower jets not operating at the design condition. The compressibility-corrected code failed to properly simulate these under-over/expanded supersonic jets. A wide series of tests was carried out to determine that the problem was due to the turbulence model. The model was then modified to account for turbulence/shock wave interaction, by adding corrections to take into account shock unsteadiness and a realizability constraint. The new model yielded good agreement with some available measurements. The new model was then used to successfully predict some actual sootblower measurements, and to study the interaction of a sootblower jet with geometries similar to tube banks in recovery boilers. A parametric study was carried out to examine the effect of the offset between a sootblower jet and a tube bank, and of deposit size on a sootblower jet. The results indicate that the shock cell structure of a jet is only slightly affected by the offset, but that the size of a deposit strongly affects the pressure exerted by the impinging sootblower jet, which depends both on the jet shock cell structure, and on the location where the interaction occurs.

Dusting is one of the major problems in the operation of lime kilns because dust particles interfere with kiln operation and reduce its efficiency. A numerical model is developed to predict the rate of dust formation in rotary lime kilns. The model consists of four major components: 1) a 3D model for the kiln gas, solving fluid flow, heat transfer, and combustion in the gas region; 2) a 1D model for the kiln bed, solving for variation of the solids composition, including moisture content, along the kiln; 3) a 3D model to predict the motion of the solids in the bed, and to estimate the reaction rates; 4) a mathematical model to predict the rate of particle pickup from the bed. Additionally, motion of dust particles was modeled, for the first time, using Stochastic Separated Flow model (a Lagrangian approach). The developed model of particle tracking enables the user to predict distribution of dust particles in the gas section of the kiln. Different components of the model were validated using experimental data published in the literature. The developed model was used to simulate operation of a full-scale lime kiln at typical operating conditions, i.e. at different fuel and air flow-rates. Dusting signatures were also estimated for each setting to determine the effect each operating condition has on dusting. The results presented in this thesis indicate that dust formation is mainly affected by the kiln gas velocity. Effect of other operating conditions was found to be negligible within the ranges studied. The results presented here suggest that dust formation can be controlled by minimizing the input gas flow rate.

Physical pick-and-place promises specificity, precision, and programmed motion, a feature making microrobotic manipulation amenable to automation for the construction of microsystems. Despite the significant progress made, a long-standing difficulty is the release of micro objects from the end effector due to strong adhesion forces at the micro scale. This research focuses on the development of microelectromechanical systems (MEMS) based microgrippers that integrate an active release mechanism for pick-and-release micromanipulation. The performance was experimentally quantified through the manipulation of 7.5-10.9µm glass spheres, and for the first time, achieves a 100% success rate in release (based on 700 trials) and a release accuracy of 0.45±0.24µm. Example patterns were then constructed through automated microrobotic pick-and-place of microspheres, achieving a speed of 6sec/sphere. To further miniaturize the devices for nanomanipulation, a novel fabrication process was developed. Through the manipulation of 100nm gold nano-particles inside a scanning electron microscope (SEM), preliminary demonstrations were made.

This thesis focuses on the development of a novel hybrid linear actuator (HLA). The research includes the optimal design, the particular fabrication, and the experimental validation. The principle of the HLA is based on the integration of the mechanisms of the solenoid actuator and the voice coil actuator. Such integration is achieved by a magnetic circuit consisting of a magnetic flux orientator, a permanent magnet, a composite shell, and a special coil. The HLA is capable of having a high repelling force at one end and a high attractive force at another end. A step-optimization technique is developed and used to determine the key parameters of the HLA, with the aid of sweeping functions in finite element analysis. Moreover, a single-pulse power supply is specially designed and prototyped for driving the HLA. The performance of the HLA is systematically characterized by simulations and experiments.

A series of steady-state water condensation experiments were conducted to determine the effects of Marangoni convection on the condensation flux. The interface was flat so that the results of the interfacial temperature discontinuities could be compared to past condensation experiments conducted under similar experimental conditions using a spherical interface. Two experimental methods were used. Method 1 was to vary the temperature in the cooling pipes (Tcp ) with the position of the interface relative to the cooling pipes fixed. Method 2 was to vary the position of the interface while Tcp was held constant. The interfacial temperature discontinuities in this study were approximately 2.3-9 times smaller in magnitude, than those measured using a spherical liquid-vapour interface. The experimental results showed that the condensation flux increased as thermocapillary convection increased (increase in interfacial temperature gradients and speed). This increase resulted in a 1.37-12.5 times enhancement in the condensation flux of pure water.

This thesis presents a novel device for measuring the viscoelastic properties of biological tissue. The ability to measure the mechanical properties of tissue is of special interest for many medical applications; ranging from disease diagnostics to surgical operations and simulations. In practice, physicians use a technique called palpation to detect the presence of viscoelastic property changes which are associated with the healthiness of tissue. Palpation relies exclusively on the expertise and experience of the physician and is only effective if the difference in tissue stiffness is profound. Current technologies for the measurement of tissue healthiness, including ultrasound, have been shown to be incapable of detecting isoechoic lesions even though they were significantly stiffer than surrounding tissue. The new device presents a reliable, accurate and quantitative method for determining the mechanical properties of soft tissue. Consequently, the healthiness of the tissue or the presence of lesions can be found.

Biobased polymers are a critical research topic as they may serve as replacement to traditional unsustainable petro-chemical polymers. It is vital to widen its range of applications by improving its physical and mechanical properties via light weighting and strength improvements. Light weighting can be accomplished by introducing foam morphology to the material while mechanical strength improvements can be achieved by inserting stiff filler material to the base polymer to form a composite. This study explores the physical, mechanical, thermal, rheological and morphological properties of blends, foams and composites between biobased PLA and PHBV matrix polymers and biobased chitin nanowhisker filler. It was found that foams produced from PLA and PHBV blends exhibits refined cellular morphology which leads to light weighting and good strength preservation while chitin nanowhiskers was determined to be a very effective filler for mechanical property improvements in both solid and porous materials.

This thesis presents a novel device for measuring the viscoelastic properties of biological tissue. The ability to measure the mechanical properties of tissue is of special interest for many medical applications; ranging from disease diagnostics to surgical operations and simulations. In practice, physicians use a technique called palpation to detect the presence of viscoelastic property changes which are associated with the healthiness of tissue. Palpation relies exclusively on the expertise and experience of the physician and is only effective if the difference in tissue stiffness is profound. Current technologies for the measurement of tissue healthiness, including ultrasound, have been shown to be incapable of detecting isoechoic lesions even though they were significantly stiffer than surrounding tissue. The new device presents a reliable, accurate and quantitative method for determining the mechanical properties of soft tissue. Consequently, the healthiness of the tissue or the presence of lesions can be found.

Biobased polymers are a critical research topic as they may serve as replacement to traditional unsustainable petro-chemical polymers. It is vital to widen its range of applications by improving its physical and mechanical properties via light weighting and strength improvements. Light weighting can be accomplished by introducing foam morphology to the material while mechanical strength improvements can be achieved by inserting stiff filler material to the base polymer to form a composite. This study explores the physical, mechanical, thermal, rheological and morphological properties of blends, foams and composites between biobased PLA and PHBV matrix polymers and biobased chitin nanowhisker filler. It was found that foams produced from PLA and PHBV blends exhibits refined cellular morphology which leads to light weighting and good strength preservation while chitin nanowhiskers was determined to be a very effective filler for mechanical property improvements in both solid and porous materials.

Flow around a cylinder is important in the motion of microorganisms found in biological viscoelastic fluids that propel themselves by flagella. Flow around a cylinder experiments are difficult to perform because of the influence of the walls and ends. An approach was developed to measure the drag on a cylinder by correcting for wall and end effects. Cylinders were vertically dipped into fluids in an annular shaped tank, which was rotated to generate a flow. The force acting on a cylinder was measured using a custom force transducer. This method was used for a Newtonian fluid and two Boger fluids. The drag of the Boger fluids was several times that of an equivalent Newtonian fluid. A cavity was observed to develop behind the cylinders once the flow surpassed a critical velocity. Streakline images taken during the experiment confirmed the presence of a wake region behind the cylinders.